Many media players, portable computers, personal digital assistants (PDAs), video game players, wireless phones and other devices now receive user inputs via proximity sensors. Typically, when a user places a finger, stylus or other input object near the proximity sensor, a capacitive, inductive, acoustic, optical, or other effect is produced that can be detected and correlated to the position of the object. This positional information can in turn be used to move a cursor or other indicator on a display screen, to scroll through text elements on the screen, or for any other user interface purpose. Although proximity sensors are readily implemented in many different types of devices, such sensors can be susceptible to accidental activation, as when a user unintentionally brushes a hand, finger, or other body part within the sensing region of the proximity sensor.
In addition to receiving proximity inputs, many devices include buttons or other sensors that detect an applied physical force. Such buttons and other force-sensitive inputs are also susceptible to accidental actuation that can result in undesired effects upon device operation. In a conventional media player, for example, an accidental bump against a table or other object can undesirably activate or deactivate the player itself, or could otherwise disrupt operation of the player. Such disruptions are particularly common (and particularly annoying) in devices that are intended to be portable, because such devices are often used in environments where they can be easily bumped or jostled.
To prevent accidental activation of force and/or proximity input sensors, many devices incorporate a mechanical “hold switch”. When the switch is activated, inputs received at one or more sensors are ignored. While the hold switch can be effective in reducing the effects of undesired inputs, such switches typically add complexity to the user interface, requiring the user to remember to engage and disengage the hold switch at appropriate times. Such switches also add bulk, cost and increased mechanical complexity to the device. Further, mechanical switches can be difficult to effectively seal against environmental effects, thereby creating a potential avenue for dust, moisture or other pollutants to enter the device.
It is therefore desirable to provide new systems and techniques for implementing modal changes in a media player, portable computer, portable telephone or other device. Such systems and techniques should be easy to implement and use, and should not require significant additional mechanical complexity. Other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.